Analogue electronic timepiece with chronographic function

Abstract: An analogue electronic timepiece with lap function, which can display a lap time correctly with the hand moving naturally. The lap time is the time taken in one lap between two interrupt signals. The present invention includes a system control circuit for outputting a control signal B in response to a signal A from an outer input means 401 to a chronograph storing means 405 for storing the value of a chronograph measuring means 404. A lap time calculating means 406 to which measured data of the chronograph measuring means 404 and former measured data stored in the chronograph storing means 405 by a former lap control signal are inputted for calculating the time difference between the above two data and outputting a correcting drive signal F if the hand requires a correcting drive as a result of the above calculation. Drive judging means 408 to which a lap input signal G, an interruption signal F, and the correcting drive signal F are inputted for outputting data of the drive number if the hand requires driving.

Description: The present invention relates to an analogue electronic timepiece with chronographic function, and in particular relates to a constitution of a hand driving control circuit for measuring a lap time during chronographic measurement. In the past, some analogue multifunction electronic timepieces have displayed the elapsed time which is termed a split time hereinafter. However, none of them have displayed the time between two points of measurement which is termed a lap time hereinafter, while the time is being measured. EP-A-0 215 345 discloses a stop watch capable of indicating plurality of split times. In such a stop watch, when a switch is depressed, hands are operated to start timing. Every time a split time switch is depressed, the time intervals between time points at which the split time switch is depressed are sequentially stored in a memory. Thus, when the switch is re-depressed, the stop watch terminates its time measurement. A plurality of split times up to the end of the time measurement can be reproduced from the later split time to the earlier split time. In contrast, EP-A-0 506 120 discloses a stop watch which can inform a time difference between a measured time and a target time and a raised or lowered degree of the measured time to the target time without complicated calculation. Such a stop watch comprises time measuring means for starting to measure time on a basis of a start command, a lap switch to be operated during a time measurement by the time measuring means, lap time means for obtaining time information from the preceding operation of the lap switch when the lap switch is operated, and hand means rotatably driven to the position of 0 o'clock when the lap switch is operated and to a position of 10 o'clock when the same time as the time information obtained by the lap time means is elapsed. U.S. 4,738,268 discloses a relative time clock in which the relative time between two or more events is recorded independently of real time or wall clock time. The time clock counts in units until the clock reaches a predetermined maximum time at which point the continuous time clock will reset and repeat its previous count cycle. The time indicated on the continuous time clock is recorded and correlated to events such as the start and finish of data recording,. A final event, such as data transfer is also correlated to the time indicated on the continuous time clock. After this date is processed the relative time of any event can be determined with respect to any other event. An explanation will now be given about split time and lap time in more detail. Fig. 2 is an explanatory diagram for explaining the function of the split and lap time. Suppose that switching operation is performed three times after chronographic measurement starts as shown in Fig. 2. When a first switching operation is done, both the split time and lap time indicate the time between the start and the switching operation. When a second switching operation is done, the split time indicates the total time from the start to the switching operation, SPLIT2. On the other hand, the lap time indicates the time between the first switching operation and the second switching operation, LAP2. Thus split time indicates the total time to the switching operation, and the lap time indicates the time between the two switching operations which are adjacent to each other. That it is say, when the switching operations are performed n times, the formula (1) below is always valid. (1) SPLIT(n) = LAP1 + LAP2 + + LAP(n) Chronographic measurement is usually performed by the following operation. An outer operating member starts to activate the timepiece. Then, an interrupting signal generating means is activated so as to generate interrupting signals at intervals of an arbitrary time. There are usually two kinds of interrupting signals and their time intervals are 1/10 second and 1 second, or 1/100 second and 1/10 second. Chronograph measurement is performed by counting these interrupting signals with a counter and so on. Particularly, in the case of an electronic timepiece having an analogue display, a hand driving control operation is performed in order to move a hand to a position in a dial corresponding to the value indicated by a counter per 1/10 second or 1 second. Any value less than the one unit of the interrupt signal is separately read in, for example a chronograph hand counter, so as to be displayed directly. Alternatively, this is not provided according to the technical specification of the product. However, when a lap time is measured by accumulating interrupt signals, it is sometimes measured to be greater than the actual lap time due to the time taken by the switching input. Fig. 3 shows two cases in which the timing of the switching input in response to an interrupt signal differ with each other. Both cases have to display a lap time comprising two interruptions and so have two drive parts. In case 2, the switching signal is inputted just before the first interruption and as a result the drive 1 corresponding to the interruption 1 is performed at once. Consequently, drive is performed for three interruptions in total until the switching input C is inputted. Therefore there exists a problem that measured data differs from display data. It is possible to display measured data correctly by setting back the hand which drives too much with a lap time calculation when the switching input C is inputted. However, it requires a hand reversion driving circuit and at the same time, it is hard for a user to trust the measurement of an electronic timepiece moving as described above. Moreover, if a chronograph interruption generating means and a chronograph measuring means are restarted at every switching input, it can prevent the hand that drives too much. However, a problem occurs in that the total time from the start is difficult to display when measurement has finished. An object of the present invention is to provide an analog electronic timepiece which displays lap time correctly without providing the hand reversion driving circuit and restarting the chronograph interruption generating means and the chronograph measuring means. The present invention prohibits the hand from driving by a first chronograph interruption in each lap time measuring section. Additionally, the present invention calculates the time difference between a former chronograph measuring data and the present chronograph measuring data, and then if there is a difference between the lap time indicated by the hand and the result of the calculation at that time, it corrects the data indicated by the hand so as to correspond to the result of the calculation. According to the present invention, there is provided an analogue electronic timepiece with chronographic function comprising: chronograph interruption generating means for outputting interruption signals; chronograph measuring means for counting the interruption signals; display means for displaying a lap time; driving means for controlling display means; characterised by lap time calculating means for determining the lap time to be displayed by calculating the time difference between the measured data of the chronograph measuring means and former measured data, and outputting a correcting drive signal to said driving means to correct said display means. In order to achieve the above-mentioned function as shown in Fig. 1, control signals B, C, and D are output following a signal A being input by an outer inputting means 1. A chronograph interrupting signal generating means 3 gives an interruption for chronographic measurement in response to the interruption control signal C outputted by a system control means 2. A chronograph measuring means 4 counts an interrupting signal E outputted by the chronograph interrupting signal generating means 3 so as to perform chronograph measurement. The chronograph measuring means 4 outputs data of chronographic measurement to a chronograph storing means 5 and a lap time calculating means 6 in response to a lap input signal B. The chronograph storing means 5 stores the latest data of chronograph measurement. The chronograph storing means 5 outputs the former data of chronographic measurement to the lap time calculating means 6 in response to the lap input signal B outputted from the system control means 2. The lap time calculating means 6 calculates a lap time from the former and the latest data of chronographic measurement, which are inputted from the chronograph measuring means 4 and the chronograph storing means 5, in response to the lap control signal B outputted from the system control means 2. As a result, if correcting drive is necessary, the lap time calculating means 6 outputs a correcting drive signal F to a drive judging means 8. The lap control signal B outputted from the system control means 2, the correcting drive signal F outputted from the lap time calculating means 6, and the chronograph interruption signal E are all inputted to the drive judging means 8. Then the drive judging means 8 calculates the drive number of the hand, judges whether drive is necessary or not, and outputs the data of the drive number to a driving means 12 only when drive is necessary. The lap control signal B outputted from the system control means 2, a reset input signal D, and the data of the drive number outputted from the drive judging means 8 are all inputted to the driving means 12. The driving means 12 actually controls the hands. The inventive electronic timepiece with chronographic function can drive a hand which is delayed from the actual lap data by one interruption of the chronograph interrupting signal E. Further, the inventive electronic timepiece with chronographic function can display a correct lap data because it conducts correcting drive of lap operation if necessary. Embodiments of the present invention will now be described with reference to the accompanying drawings, of which: Fig. 1 is a functional block diagram showing one example of a basic constitution according to the present invention; Fig. 2 is an explanatory diagram showing the function of split and lap time according to the present invention; Fig. 3 is a timing diagram showing lap operation according to the present invention; Fig. 4 is a circuit diagram of an embodiment of the inventive electronic timepiece; Fig. 5 is a flow chart showing a lap time calculating means of the present invention by a soft program; Fig. 6 is a flow chart showing a drive judging means of the present invention by a soft program; Fig. 7 is a structual diagram showing a drive control means of the present invention; and Fig. 8 is an explanatory diagram showing operation of the present invention. An embodiment of the present invention will be described with reference to the drawings. Fig. 4 is a circuit diagram showing an embodiment of the inventive electronic timepiece. A direction to start chronographic measurement is inputted from an outer input switch 401, such as a button switch. A system control circuit 402 judges an inputted signal to be a start or a stop or a lap and so on, and then outputs control signals to a chronograph interruption generating circuit 403, chronograph counter 404, a chronograph storing circuit 405, a drive control means 410, a target hand position storing circuit 409, a drive judging means 408 and so on respectively. The target hand position storing circuit 409 is constituted of a counter or other such component. Thus, for example, when a start signal is inputted, an interruption signal generating control signal C is outputted to the chronograph interruption generating circuit 403 and a drive waiting signal G which will be explained hereinafter is outputted to the drive judging means 408. When lap operation is inputted, a lap control signal B is outputted to the chronograph counter 404 in order to output the present value to a lap time calculating circuit 406 and the chronograph storing circuit 405. As well, when lap operation is inputted and a lap control signal B for storing the latest chronograph counter value which is inputted from the chronograph counter 404 is outputted, the former chronograph value, which is stored when the former lap operation is inputted to the chronograph storing circuit 405, is outputted to the lap time calculating circuit 406. The chronograph interruption generating circuit 403 outputs a chronograph interruption signal E to the chronograph counter 404 and the drive judging circuit 408 at arbitrary intervals according to an interruption signal generating control signal C which is outputted from the system control circuit 402. In this embodiment, a chronograph interrupting signal E is outputted to the drive judging circuit 408 each second and to the chronograph counter 404 each 1/10 second. The chronograph counter 404 counts a chronograph interrupting signal E and then counts a total value of chronographic measurement. The chronograph counter 404 outputs the present chronograph value to the lap time calculating circuit 406 and the chronograph storing circuit 405 when a lap control signal B is inputted from the system control circuit 402. The chronograph storing circuit 405 usually stores the former chronograph value which is stored when the former lap control signal B is inputted. The chronograph storing circuit 405 outputs the former chronograph value stored therein to the lap time calculating circuit 406 when a lap control signal B is newly inputted thereto. The chronograph storing circuit 405 stores new data of chronographic measurement newly outputted from the chronograph counter 404. The chronograph storing circuit 405 is reset and stores zero at starting operation of chronographic measurement. The lap time calculating circuit 406 begins to operate in response to a lap control signal B outputted from the system control circuit 402. Fig. 5 is a schematic flow chart showing the lap time calculating circuit 406 embodied by a soft program. When a lap control signal B is inputted (Step 501), the lap time calculating circuit receives the present data of chronographic measurement and the former data of chronographic measurement (Steps 502 and 503), and then calculates a lap time with the following formula (Step 504): (The present data of chronographic measurement) ---(The former data of chronographic measurement). Next, the present and former data is compared by comparing the least significant digits: that is to say, the value of the smallest unit of chronographic measurement is compared (Step 505). In this embodiment, the smallest unit of lap display is 1 second and that of chronographic measurement is 1/10 second, so the values are compared in 1/10 second digits. In this case, when the value of the former chronographic measurement data in 1/10 second digits is larger than that of the present chronograph measurement data in 1/10 second digits the operation is ended (Step 507). The carry signal is generated by the calculation in the step 504. When the value of the present chronographic measurement data in 1/10 second digits is larger than or equal to that of the former chronographic measurement data in 1/10 second digits the operation is ended (Step 507) after outputting a correcting drive signal F (step (506). The carry signal is not generated by the calculation in the Step 504 in this case. The correcting driver signal is used for conducting correcting drive to the drive judging circuit 408. A drive waiting signal G outputted from the system control circuit 402, a chronograph interrupting signal E outputted from the chronograph interruption generating circuit 403, and a correcting drive signal F outputted from the lap time calculating circuit 406 are inputted to the drive judging circuit 408. The drive judging circuit 408 judges whether drive is conducted or not and as a result if drive is conducted, outputs the data of drive number. Fig. 6 is a schematic flow chart showing the drive judging circuit 408 embodied by a soft program. If a drive waiting signal G is inputted to the drive judging circuit 408 when measurement begins (Step 601), a drive prohibition flag is mounted therein (Step 605) so as to end the operation (Step 608). When measurement begins and a chronograph interrupting signal E is inputted to the drive judging circuit 408 each a second (Step 602), the drive judging circuit 408 judges whether the drive prohibition flag stands or not (Step 604) and as a result if the drive prohibition flag stands, knocks the flag down so as to end the operation (Step 608). In other words, when a first chronograph interrupting signal E is inputted since lap measurement begins, the drive judging circuit 408 ends the operation thereof without outputting the drive data to the target hand position storing circuit 409. Thus, it follows that drive of the hand is not conducted. When lap operation or stop operation of chronographic measurement is conducted, the lap time calculating circuit 406 calculates a lap time. In this stage, when a correcting drive signal F is inputted because the value of 1/10 second digits in the former data is larger (Step 603), the drive data comprising six shots, which correspond to a correcting drive pulse for one second, is outputted to the target hand position storing circuit 409 (Step 607), and then the operation is ended (Step 608). When the drive data is outputted, the target hand position storing circuit 409 calculates the position to which the hand must be transferred and the drive control circuit 410 calculates a necessary drive number with data of a present hand position storing circuit 407. A structure diagram of the drive control circuit 410 is shown with Fig. 7. The drive control circuit 410 comprises a control circuit 701 for controlling transfer of the data and output of a drive control signal, a calculating circuit 702 for calculating data of a drive number, a waveform shaping circuit 703 for outputting a driving pulse to a motor of a hand, and a waveform outputting circuit 704 for outputting pulses to a required number. The control circuit 701, when a lap control signal B is inputted from the system control circuit 402 thereto, inputs each data from the present hand position storing circuit 407 and the target hand position storing circuit 409, and then outputs a drive amount calculating signal G for calculating the number of drive pulses which is necessary to transfer the hand to the calculating circuit 702. The calculating circuit 702 outputs the data of the number of drive pulses to the waveform outputting circuit 704 after calculating the number of drive pulses. The waveform outputting circuit 704 comprises a counter and so on. The waveform outputting circuit 704 sets data of the number of drive pulses to the counter, and then subtracts a counter value every time it outputs a waveform outputted from the waveform shaping circuit 703 to a motor 711. When the counter value becomes zero, the waveform outputting circuit 704 stops outputting a waveform so as to end predetermined drive. A flow of operation will be explained with concrete numerical values. Fig. 8 is an explanatory diagram showing movement of the hand when lap operation is conducted n times, n+1 times, and m times, m+1 times. In Fig. 8, suppose that n-th lap operation is inputted when the data of chronographic measurement is 9.8 second. The chronograph storing circuit 405 stores the data of 9.8 second. The drive judging circuit 408 sets a drive prohibition flag therein. Next, a chronograph interruption signal E is inputted from the chronograph interruption generating circuit 403 to the drive judging circuit 408 at ten seconds after chronographic measurement begins. Then the drive judging circuit 408 resets the drive prohibition flag which has been set until then, and stops its operation without conducting drive of the hand. Therefore the hand displaying lap time doesn't move and keeps on indicating zero, as shown in a timepiece - A. Next, a chronograph interruption signal E is inputted from the chronograph interruption generating circuit 403 to the drive judging circuit 408 at the eleventh second after chronographic measurement begins. But the drive prohibition flag has been reset and therefore drive data comprising six steps which are drive steps enough to display lap time for one second is outputted to the driving circuit 12. The driving circuit 12 outputs drive waveforms for six steps according to the preceding operation. Consequently, the timepiece B displaying lap time indicates one second. When the twelve seconds chronograph interruption signal E is inputted to the drive judging circuit 408, a similar operation is conducted and then the timepiece C displaying lap time indicates two seconds. Next, if (n + 1)th lap operation is conducted when the chronographic measurement time is 12.7 second, the chronograph counter 404 outputs the data of 12.7 second which indicates the present chronographic measurement data, to the chronograph storing circuit 405 and the lap time calculating circuit 406. The chronograph storing circuit 405 outputs the data of 13.8 seconds which indicates the former chronographic measurement data stored therein at that time, to the lap time calculating circuit 406. The chronograph storing circuit 405 stores newly the present chronographic measurement data, 12.7 seconds. The lap time calculating circuit 406 calculates (n+1)th lap data with each chronographic measurement data, 13.8 seconds and 12.7 seconds. The lap time calculating circuit 406 compares values of the 1/10 second digits. In this case, the former data indicates 8 and the present data indicates 7, so the former data is larger than the other. Therefore correcting drive is not outputted and the operation is ended. At that time, the hand remains at two seconds to which the hand has transferred at the twelfth chronographic interruption signal and doesn't move any more. Hence (n+ 1)th lap time indicates two seconds. An actual lap time is as follows; 12.7 seconds - 9.8 seconds = 2.9 seconds. However, if the fractions in the smallest digit are dropped according to the specification of this product, the hand displays lap time exactly. Then, similarly, a description will be given for the case that an m-th lap operation is inputted when a chronographic measurement data is 9.8 seconds and further an (m+1)th lap operation is inputted when a chronographic measurement data is 12.9 seconds. The timepiece acts similarly until 12 seconds and the hands display the identical lap time in the timepieces A, B, and C. Next, if an (m+1)th lap operation is inputted when the elapsed time of chronograph measurement is 12.9 seconds, the chronograph counter 404 outputs the present chronographic measurement data of 12.9 seconds to the chronograph storing circuit 405 and the lap time calculating circuit 406. The chronograph storing circuit 405 outputs the former chronographic measurement data of 10.8 seconds, which is stored therein at that time, to the lap time calculating circuit 406. The chronograph storing circuit 405 stores newly the data of 12.9 seconds which indicates the latest chronographic measurement. The lap time calculating circuit 406 calculates the (m+1)th lap data from each chronographic measurement data, 12.9 seconds and 9.8 seconds and further compares the values of a 1/10 second digits. In this case, the former data is 8 and the present data is 9, so the present data is larger than the other. Therefore, a correcting drive signal F is outputted to the drive judging circuit 408 and then the operation is ended. The drive judging circuit 408 to which the correcting drive signal F is inputted outputs drive data comprising six steps which are transferring steps for one second to the motor 711. The motor 711 to which the drive data is inputted transfers clockwise the hand for one second through a gear train and so on. Therefore the hand is transferred from the position of two seconds, to which the hand is moved when the twelfth chronographic interruption is generated, to the position of three seconds. As shown with the timepiece E, (m+1)th lap time is three seconds. The actual time is as follows. 12.9 seconds - 9.8 seconds = 3.1 seconds. However, the timepiece indicates a lap time correctly according to the specification of the product. As described above, the inventive timepiece with chronographic function comprises the system control means for outputting a control signal to each means in response to a signal inputted from the outer inputting means. The chronograph storing means for storing a value of the chronograph measuring means by a lap control signal outputted from the system control means. The lap time calculating means to which a measurement data of the chronographic measuring means and a former measuring data stored in the chronographic storing means by a former lap control signal are inputted for calculating the time difference between the above two measured data and outputting a correcting drive signal if correcting drive is required for the hand as a result of the above calculation. The drive judging means to which a lap input signal, an interruption signal, and a correcting drive signal each of which are outputted from the system control means are inputted for outputting the data of a drive number if the hand requires driving. Therefore, the hand reversion driving circuit is not required to provide the inventive timepiece. As well, the chronograph interruption generating means and the chronograph measuring means do not require to resetting. Consequently, the inventive timepiece can display a lap time correctly with the hand moving naturally. The aforegoing description has been given by way of example only and it will be appreciated by a person skilled in the art that modifications can be made without departing from the scope of the present invention as claimed.

Claims: An analogue electronic timepiece with chronographic function comprising: chronograph interruption generating means (403) for outputting interruption signals (E); chronograph measuring means (404, 405) for counting the interruption signals (E) ; display means for displaying a lap time; driving means (412) for controlling said display means; characterised by lap time calculating means (406) for determining said lap time to be displayed by calculating the time difference between the measured data of the chronograph measuring means (404, 405) and former measured data, and outputting a correcting drive signal (F) to said driving means (412) to correct said display means. An analogue electronic timepiece according to claim 1, wherein the chronograph measuring means (404, 405) comprises chronograph storing means (405) for storing measured data of the chronograph measuring means. An analogue electronic timepiece according to claim 1 or 2, wherein the driving means comprises: target hand position storing means (409) for storing data of target hand position; present hand position storing means (407) for storing data of present hand position; and hand position calculating means (410) to which the data of the target hand position storing means (409) and present hand position storing means (407) is inputted, for calculating the driving signal of the display means. An analogue electronic timepiece according to claim 1, 2 or 3, wherein the lap time calculating means (406) compares the values of the smallest unit of chronographic measurement. An analogue electronic timepiece according to any one of the preceding claims, wherein the driving means (412) output corrects the display means by one second intervals.

Inventors: MASAKI HIROYUKI, MASAKI, HIROYUKI, MASAKI, HIROYUKI, C/O SEIKO INSTRUMENTS INC
Applicants: SEIKO INSTR INC, SEIKO INSTRUMENTS INC.
Application year: 1994
Main classification: G04F8
IPC codes: G04F8, G04C3